Various means have been developed for securing dentures to existing teeth or to the jawbone. In the attachments to existing teeth, the retaining means usually involves a groove or channel formed or inserted in a fabricated ceramic metal crown cemented on the teeth and a matching tongue or pin built into the denture, the tongue sliding into the channel as the denture is seated. Retention is by frictional grip of the tongue in the channel and requires a precision fit for security.
If the fit is close enough for securely holding the denture, the attachment is usually very rigid and does not permit the very slight motion of the denture that is desirable to accommodate a comfortable chewing action. Resilient inserts or cushions have been used but these are subject to wear and require periodic replacement. A typical example of this is described in U.S. Pat. No. 4,362,509 to J. M. Sulc, which has a dovetail-type connection with a plastic insert, the plastic part engaging a very small locking rib that is subject to wear.